Manufacture of paper-board



Patented Mar. 14, 1933 PAUL 1:. scenes, or im iee ue aimi g;

MANUFACTURE or rarna nonn'n 5 No Drawing.

This invention has reference to the manufacture of paper or paper-boardand more articularly to the corrugated sheet form- 5 sheets now widelyused for a variety of purposes and known as box board; but the inventionis not restricted to that use.

Heretofore' the corrugated sheet of box board has been most commonlymade from straw-board, which has the necessary or desirable qualitieswhen the weight of the y sheet, at the standard thickness of 0.009 of aninch, is from 32 to 34 pounds per thousand square feet. V In view of theuses to which corrugated paper-board is put, it is very desirable toreduce the weight thereof if that can be done without loss in respect ofother essential characteristics.

It has been attempted, therefore, to produce a paper-board suitable forcorrugating (known in the trade as corrugating board) that is to say, apaper-board having the properties of rigidit lightness and running wellin the corrugating machine by using a pulp made of a wood fiber (pinewood pulp) which is substantially lighter than that fromwhich thecommercial corrugated strawboard is made; but it has been found that thegain in lightness was at the expense of some of the essential ordesirable properties of the finished corrugated sheet.

Use has also been made, in the manufacture of corrugating board, of ulpobtained by the semi-chemical process rom chestnut chips. This producthas been found satisfactory as regards strength and other propertieswhen the weight is approximately 34 pounds per 1000 square feet; butthis material cannot be used for the specified purpose at asubstantially less weight without loss in res ect to rigidity andbending quality.

ne of the leading objects of the present invention is to produce a paperstock suitable for makin corrugating board which, at the standard tickness, will have a weight substantially less than that of a sheet madefrom the pulp last referred to, or made of. e.

straw-board, without sacrificing any of essential or desirableproperties thereof.

ature, and. by any appropriateimeans, appr ved a e of b t ng engine-.such. as

Application filed September 2, 11931 *seriai noi 550,865."

' I Another object ofltlie weight "at the standard thickness, possessesthe other sheets cial fabric. The foregoing and other objectsof the in.-

duce, at relativelyajlow cost, corrugatmg board which,.. while z-having;a {minimum mg one member of the two-ply or three-ply vention areattained by, the admixture with semi-chemical pulp, known as phite pulp,a product developed by-the-US.

term cotton fibers is 1 used-Therein in. a? ge-:

neric; sense embracing; linters and hull Efib'ers.

1 and 10. {t0 25, percent; of -cottonfibers by weight. 1

beating-engine, but may .be. eigfected atwany neutral su-l- ,Forest,PlOducts- Laboratory, of; ,a certain ll proportion of cottonfibersisuchaslintensor .hullfibers, The cotton fibers? maybeused :to, goodiadvantagein a raw;.-staite, thereby;

saving the cost of cooking or treating-V. The,

.improved characteristics 1in..;respect towbend -;in'g; and resistantpropertieszandiin respectto its. capacity for qu-ickly; absorbing gluewhereby the corrugated sheetis attaclifid i (or sheet), of thecammer wconvenient stage of the-process of manufac- I Any the l-lollander, maybe used; .7

One advan age us sult of the invention .isgthat itpermits theutilization 10f theghull fibers of the cotton seed, thereby jefiectiggsa substantial savingjincost. These low cost hull fibers may be usedwithout any preliminary treatment for cleansing or other purpose.

It is not necessary for the purposes of this invention that the fibersbe separated entire-1;.

ly from the hulls; as the hulls with attached fibers may be chemicallydigested and in that state admixed with the semi-chemical or 1 otherstandard pulp.

out impairing its other desirable character istic's, but rather with animprovement As already stated, the principal advantaged recently madeavailable) standard -gree the required rigidity,

capacity to maintain the j to Withstand pressure and I 'WllllB thecotton linters or hull fibers fur- -nishthe requisite bulk and alsoimpart to is, the capacity to run therein. Thus, by the use of theproportion of cotton fiber stated above, the Weight of the sheet ofstandard thickness (0009) may be reduced one fourth or more. That is,instead of running from32 to 34 pounds per 1000 square feet, its Weightmay be reduced to from '24 to 26 pounds per 1000 square feet or evenless. And since the price is based upon the area ofthe sheet and notupon its Weight, the gain in the Value of the product per ton issubstantial.

I have found that in paper board made of semi-chemical or neutralsulphite pulp and cotton fibers (linters or; semi-chemical pulp impartsin ample de- Which is of prime importance in corrugating board, that is,the

to absorb shocks;

the pulp the-necessary bending quality, that well on thecorrugatingmachines and to take readily the impress of the corrugatingdevices. I have found that cotton hull fibers (a product only quality."

Furthermore, since the hull fibers cost less per poundthan thesemi-chemical pulp, the cost of the aggregate is reduced in 'portion to'the; percentage of hull fibers in i the mixturespecification.

1. 'Corrugating paper-boardcomposed of semi-chemical pul' havlng inadmixture therewith cotton fibers Corrugating paper-board composed ofsemi-chemical pulp having in admixture therewith cotton fibers in theproportion of from about tento abouttwenty-five percent of the mass byweight. 1 I 3. Corrugating paper-board composed of semi-chemical pulphaving in admixture therewith cotton fibers in the proportion of aboutten percent of the mass by weight.

whereof I have signed this In testimony PAUL H. ROGERS.

hull fibers) th a corrugated form,

impart to anypulp a -very superior running pro-

